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Performance

· 16 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.
SCORE
72
GRADE
C
FIX
5
REVIEW
2
PASS
7
INFO
2

Performance-focused optimization plan with CWV assessment, top offenders, and time estimates

Mobile Desktop
32
Performance Overall performance score (0–100) based on Core Web Vitals and other metrics. 90+ is good.
86
Accessibility Measures how accessible the page is for users with disabilities. Checks color contrast, ARIA labels, and semantic HTML.
77
Best Practices Checks for modern web development best practices including HTTPS, no console errors, and secure JavaScript.
100
SEO Measures basic SEO optimizations: meta tags, crawlability, link text, and mobile friendliness.

First Contentful Paint First Contentful Paint — how long until the browser renders the first piece of content. Under 1.8s is good.

11.60 s

Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.

22.12 s

Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.

1.13 s

Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.

0.000

Speed Index Speed Index — how quickly content is visually displayed during load. Under 3.4s is good.

11.60 s

Time to Interactive Time to Interactive — how long until the page is fully interactive and responds to user input. Under 3.8s is good.

22.37 s

Page Load Progression

375 ms
750 ms
1.1 s
1.5 s
1.9 s
2.2 s
2.6 s
3.0 s
Checks
16
7 PASS 2 REVIEW 5 FIX
F
Page Weight Budget
Action
3.5 MB transferred, 154 requests
FIX
3.5 MB transferred, 154 requests
Warning::
Page weighs 14.6 MB (3.5 MB transferred)
Warning::
JavaScript is 1.9 MB — consider code splitting or lazy loading
Large JavaScript bundles delay interactivity. Split code by route or defer non-critical scripts.
Got: 1.9 MB
Warning::
154 HTTP requests — consider bundling or reducing
Each request adds latency. Bundle small files, use sprites, or eliminate unnecessary requests.
Info::
Estimated 0.74 g CO2 per page load
3.5 MB / 2.4 MB budget
3.5 MB transferred
154 requests
0.74 g CO2 per page load
JavaScript 1.9 MiB 55%
Other 802.4 KiB 22%
Images 506.0 KiB 14%
Fonts 186.2 KiB 5%
CSS 84.1 KiB 2%
HTML 32.7 KiB 1%
Other 15.9 KiB 0%
Other 6.4 KiB 0%
Other 971 B 0%
Other 0 B 0%
0 2.4 MB 4.9 MB
Over budget

Large JavaScript bundles delay interactivity. Split code by route or defer non-critical scripts.

Why this matters

JavaScript bundle is large — code-split routes and lazy-load off-screen components to defer.

Source: web.dev

Each request adds latency. Bundle small files, use sprites, or eliminate unnecessary requests.

Why this matters

High HTTP request count — bundling, sprite-ing, and HTTP/2 server push can reduce per-request overhead.

Source: web.dev

D
Third-Party Impact
Action
100% third-party, 0 ms blocking
FIX
100% third-party, 0 ms blocking
Warning::
Third-party code accounts for 100% of page weight (3.5 MiB of 3.5 MiB)
Info::
Third-party blocking time is low (0 ms)
100%
First-party Third-party
F
JS Execution Cost
Action
7944ms total JS execution
FIX
7944ms total JS execution
Warning::
Unattributable: 2725ms CPU time
Warning::
https://www.gstatic.com/recaptcha/releases/kUYUkUl...: 1693ms CPU time
Warning::
https://d35aaqx5ub95lt.cloudfront.net/js/app-cf122...: 1610ms CPU time
Warning::
https://d35aaqx5ub95lt.cloudfront.net/js/6057-b284...: 1037ms CPU time
Info::
https://www.googletagmanager.com/gtm.js?id=GTM-TX6...: 200ms CPU time
Warning::
Third-party scripts: 7752ms (98% of total)

Main Thread Breakdown

Script Evaluation 51% Other 28% Style & Layout 8% Script Parsing & Compilation 6% Garbage Collection 5%
ScriptTotalScriptingParse/CompileParty
Unattributable2725ms98ms0ms3rd
https://www.gstatic.com/recaptcha/releases/kUYUkUlSyqkjTSMaN2w3RaOh/recaptcha__en.js1693ms1270ms77ms3rd
https://d35aaqx5ub95lt.cloudfront.net/js/app-cf122905.js1610ms1289ms99ms3rd
https://d35aaqx5ub95lt.cloudfront.net/js/6057-b2849109.js1037ms811ms98ms3rd
https://www.googletagmanager.com/gtm.js?id=GTM-TX6Z97C200ms159ms37ms3rd
https://www.duolingo.com/192ms5ms4ms1st
https://www.googletagmanager.com/gtag/js?id=AW-728842606&cx=c&gtm=4e6460191ms151ms31ms3rd
https://cdn.cookielaw.org/scripttemplates/202404.1.0/otBannerSdk.js160ms66ms54ms3rd
https://d35aaqx5ub95lt.cloudfront.net/js/5314-33cb86aa.js74ms47ms12ms3rd
https://accounts.google.com/gsi/client61ms32ms29ms3rd
F
JS Bundles
Action
30 scripts, 1.1 MB unused
FIX
30 scripts, 1.1 MB unused
Warning::
https://d35aaqx5ub95lt.cloudfront.net/js/app-cf122...: 181 KB unused (58%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://www.gstatic.com/recaptcha/releases/kUYUkUl...: 179 KB unused (49%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://www.gstatic.com/recaptcha/releases/kUYUkUl...: 179 KB unused (49%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://www.gstatic.com/recaptcha/releases/kUYUkUl...: 179 KB unused (49%)
Consider code splitting or tree shaking to reduce unused code.
Warning::
https://d35aaqx5ub95lt.cloudfront.net/js/6057-b284...: 138 KB unused (58%)
Consider code splitting or tree shaking to reduce unused code.
Info::
Total unused JavaScript: 1.1 MB
1170 KB unused JavaScript

Downloaded but never executed on this page.

ScriptSizeUnusedMinifiedParty
https://d35aaqx5ub95lt.cloudfront.net/js/app-cf122905.js316 KB181 KB (58%)✓3rd
https://www.gstatic.com/recaptcha/releases/kUYUkUlSyqkjTSMaN2w3RaOh/recaptcha__en.js363 KB179 KB (49%)✓3rd
https://www.gstatic.com/recaptcha/releases/kUYUkUlSyqkjTSMaN2w3RaOh/recaptcha__en.js0 KB179 KB (49%)✓3rd
https://www.gstatic.com/recaptcha/releases/kUYUkUlSyqkjTSMaN2w3RaOh/recaptcha__en.js363 KB179 KB (49%)✓3rd
https://d35aaqx5ub95lt.cloudfront.net/js/6057-b2849109.js237 KB138 KB (58%)✓3rd
https://www.googletagmanager.com/gtm.js?id=GTM-TX6Z97C166 KB91 KB (55%)✓3rd
https://accounts.google.com/gsi/client93 KB73 KB (78%)✓3rd
https://cdn.cookielaw.org/scripttemplates/202404.1.0/otBannerSdk.js109 KB67 KB (62%)✓3rd
https://www.googletagmanager.com/gtag/js?id=AW-728842606&cx=c&gtm=4e6460137 KB61 KB (44%)✓3rd
https://d35aaqx5ub95lt.cloudfront.net/js/5314-33cb86aa.js46 KB22 KB (50%)✓3rd

Consider code splitting or tree shaking to reduce unused code.

Why this matters

This bundle has high unused code — code-split or tree-shake to ship only what executes.

Source: web.dev / Lighthouse coverage

Consider code splitting or tree shaking to reduce unused code.

Why this matters

This bundle has high unused code — code-split or tree-shake to ship only what executes.

Source: web.dev / Lighthouse coverage

Consider code splitting or tree shaking to reduce unused code.

Why this matters

This bundle has high unused code — code-split or tree-shake to ship only what executes.

Source: web.dev / Lighthouse coverage

Consider code splitting or tree shaking to reduce unused code.

Why this matters

This bundle has high unused code — code-split or tree-shake to ship only what executes.

Source: web.dev / Lighthouse coverage

Consider code splitting or tree shaking to reduce unused code.

Why this matters

This bundle has high unused code — code-split or tree-shake to ship only what executes.

Source: web.dev / Lighthouse coverage

D
HTTP Caching
Action
no-store (uncacheable)
FIX
no-store (uncacheable)
Info::
Cache-Control: no-store prevents all caching
Intentional for dynamic content, but increases server load for every page view.
Got: no-store, no-cache, must-revalidate, proxy-revalidate
Info::
No ETag or Last-Modified header
Conditional requests (304 Not Modified) are not possible without validators.
Cache-Control

no-store, no-cache, must-revalidate, proxy-revalidate

DirectiveValueMeaning
no-store—Never cache this response
no-cache—Cache but always revalidate first
must-revalidate—Must recheck with server after expiry
proxy-revalidate—
B
Image Optimization
58 images, 0 KB saveable
REVIEW
58 images, 0 KB saveable
Warning::
https://d35aaqx5ub95lt.cloudfront.net/images/splas... is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
58 images 506 KB
0 oversized -0 KB
58 legacy format
1 missing dimensions CLS risk

Set explicit width and height to prevent CLS.

Why this matters

Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.

Source: web.dev / Core Web Vitals

C
Green Hosting
Action
Whether the site is served from green-energy infrastructure
REVIEW

Green Hosting

No green hosting detected

A+
Text Compression
All text resources are compressed
PASS
All text resources are compressed
Info::
All text resources are compressed
All text resources are properly compressed.
A+
Font Loading
4 fonts (186 KB)
PASS
4 fonts (186 KB)
Info::
4 font(s) use font-display: swap (FOUT risk but functional)

Web fonts

4

186 KB total

Render-blocking

0

of 4

Dominant font-display

swap

Most common across fonts

Font loading timeline
Transfer FOIT (block) FOUT (swap)
0 ms 2.0 s 4.0 s 6.0 s 8.0 s 10.0 s 12.0 s 14.0 s 16.0 s 18.0 s 20.0 s 22.0 s FCP 11.6 s LCP 22.1 shttps://d35aaqx5ub95lt.cloudfront.net/fonts/642e24bb0295f3aee4dedcd8eecd8007.woff2642e24bb0295f3aee4dedcd... https://d35aaqx5ub95lt.cloudfront.net/fonts/642e24bb0295f3aee4dedcd8eecd8007.woff2 — 63.0 KiB — 0 ms — font-display: swaphttps://d35aaqx5ub95lt.cloudfront.net/fonts/a96f1b78ebf295556c0e9500cde6dd64.woff2a96f1b78ebf295556c0e950... https://d35aaqx5ub95lt.cloudfront.net/fonts/a96f1b78ebf295556c0e9500cde6dd64.woff2 — 63.8 KiB — 0 ms — font-display: swaphttps://d35aaqx5ub95lt.cloudfront.net/vendor/68d22534874c554b0c9ebabea379fc60.woff268d22534874c554b0c9ebab... https://d35aaqx5ub95lt.cloudfront.net/vendor/68d22534874c554b0c9ebabea379fc60.woff2 — 25.5 KiB — 0 ms — font-display: swaphttps://fonts.gstatic.com/s/roboto/v48/KFO7CnqEu92Fr1ME7kSn66aGLdTylUAMa3yUBHMdazQ.woff2KFO7CnqEu92Fr1ME7kSn66a... https://fonts.gstatic.com/s/roboto/v48/KFO7CnqEu92Fr1ME7kSn66aGLdTylUAMa3yUBHMdazQ.woff2 — 33.9 KiB — 0 ms — font-display: swap
642e24bb0295f3aee4dedcd... woff2 swap
Size 63 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
a96f1b78ebf295556c0e950... woff2 swap
Size 64 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
68d22534874c554b0c9ebab... woff2 swap
Size 25 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
KFO7CnqEu92Fr1ME7kSn66a... woff2 swap
Size 34 KB
Load time 0 ms
Start 0 ms
Risk FOUT — text flashes from fallback to web font
Optimization checklist
  • Preload critical fonts (priority=high)
  • Use woff2 format for all fonts
  • Set font-display to swap, optional, or fallback
  • Subset large fonts (≤100 KB each)
A+
Resource Caching
All resources properly cached
PASS
All resources properly cached
Info::
No caching issues found
All static resources have appropriate caching headers.
A+
Critical Rendering Path
No render-blocking resources
PASS
No render-blocking resources
Info::
No render-blocking resources detected
A+
Resource Hints
No optimization needed
PASS
No optimization needed
Info::
No resource hint issues
A+
Render-Blocking Resources
No render-blocking resources detected
PASS
No render-blocking resources detected
Info::
No render-blocking resources detected in <head>
A+
Third-Party Resources
No third-party resources detected
PASS
No third-party resources detected
Network Waterfall
154 requests over 0ms
INFO

Performance analysis not available for this result.

Third-Party Script Cost
Per-script blocking time, transfer cost, and cache headers
INFO
98% of JavaScript execution is third-party
First-party Third-party 7752ms · 1105KB · €124/mo
Unattributable
Other
Costly
Execution 2725ms
Transfer 0 KB
Monthly Cost €44/mo
www.gstatic.com
Other
Costly
Execution 1693ms
Transfer 0 KB
Unused 49%
Monthly Cost €27/mo
d35aaqx5ub95lt.cloudfront.net
Other
Costly
Execution 1610ms
Transfer 316 KB
Unused 58%
Monthly Cost €26/mo
d35aaqx5ub95lt.cloudfront.net
Other
Costly
Execution 1037ms
Transfer 237 KB
Unused 58%
Monthly Cost €17/mo
Google Tag Manager
Tag Manager
Costly
Execution 200ms
Transfer 166 KB
Unused 55%
Monthly Cost €3/mo
Google Tag Manager
Tag Manager
Optional
Execution 191ms
Transfer 137 KB
Unused 44%
Monthly Cost €3/mo
OneTrust
Consent
Essential
Execution 160ms
Transfer 109 KB
Unused 62%
Monthly Cost €3/mo
d35aaqx5ub95lt.cloudfront.net
Other
Optional
Execution 74ms
Transfer 46 KB
Unused 50%
Monthly Cost €1/mo
accounts.google.com
Other
Optional
Execution 61ms
Transfer 93 KB
Unused 78%
Monthly Cost €1/mo

These scripts may cost more than they're worth

  • Unattributable adds 2725ms and costs ~€44/month
  • www.gstatic.com adds 1693ms and costs ~€27/month
  • d35aaqx5ub95lt.cloudfront.net adds 1610ms and costs ~€26/month
  • d35aaqx5ub95lt.cloudfront.net adds 1037ms and costs ~€17/month
  • Google Tag Manager adds 200ms and costs ~€3/month

98% of JavaScript execution time is spent on third-party scripts. Consider auditing which scripts are essential.

Why this matters

When third-party JS execution time exceeds your own, performance gains from frontend work are capped by code you don't own.

Learn more ▾

Every millisecond of third-party JS competes with your own for main-thread time. If their share is bigger than yours, optimization on your code base barely moves the needle. Audit, defer, or remove third-parties before further frontend optimization. Use Lighthouse's third-party audit to identify the worst offenders.

Source: web.dev

Unattributable takes 2725ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.

Why this matters

This script has high main-thread execution time — optimize hot paths or defer.

Source: web.dev

www.gstatic.com takes 1693ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.

Why this matters

This script has high main-thread execution time — optimize hot paths or defer.

Source: web.dev

d35aaqx5ub95lt.cloudfront.net takes 1610ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.

Why this matters

This script has high main-thread execution time — optimize hot paths or defer.

Source: web.dev

58% of d35aaqx5ub95lt.cloudfront.net's code is unused. The script may be loading features you don't use.

Why this matters

Bundle has high unused-code ratio — tree-shaking and route-splitting recover the wasted bytes.

Source: web.dev

d35aaqx5ub95lt.cloudfront.net takes 1037ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.

Why this matters

This script has high main-thread execution time — optimize hot paths or defer.

Source: web.dev

58% of d35aaqx5ub95lt.cloudfront.net's code is unused. The script may be loading features you don't use.

Why this matters

Bundle has high unused-code ratio — tree-shaking and route-splitting recover the wasted bytes.

Source: web.dev

Google Tag Manager takes 200ms of CPU time. Consider loading it asynchronously or replacing it with a lighter alternative.

Why this matters

This script has high main-thread execution time — optimize hot paths or defer.

Source: web.dev

55% of Google Tag Manager's code is unused. The script may be loading features you don't use.

Why this matters

Bundle has high unused-code ratio — tree-shaking and route-splitting recover the wasted bytes.

Source: web.dev

62% of OneTrust's code is unused. The script may be loading features you don't use.

Why this matters

Bundle has high unused-code ratio — tree-shaking and route-splitting recover the wasted bytes.

Source: web.dev

78% of accounts.google.com's code is unused. The script may be loading features you don't use.

Why this matters

Bundle has high unused-code ratio — tree-shaking and route-splitting recover the wasted bytes.

Source: web.dev

How third-party costs are calculated

All checks on this page are automated. Results are estimates - run targeted manual reviews when the score affects a release decision.

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